Parrot communication in the wild from Karl Berg on Vimeo.
What's the News: Parrots, those irrepressible mimics of the animal world, are some of the few creatures known to have individual names: each bird has its own signature call that others use when addressing it and that the bird uses itself in avian "conversation." Scientists have long wondered where these calls come from. Now, a new study of wild parrots
shows that even before chicks can "talk," their parents have provided them with a moniker, which they will tweak and then use throughout their lives.
How the Heck:
While scientists have long known that parrots use signature calls and watched captive birds do it, they wanted to see how wild birds get names: are they biologically innate, chosen by each parrot itself, or somehow assigned by Mom and Dad?
To study this, the researchers set up video cameras in 16 green-rumped parrotlet nests in Venezuela, part of a large wild population that has been living since 1987 in nesting tubes provided by scientists.
To probe the question of whether calls were innate, they shuffled eggs around so that half the population was raising chicks not genetically related to them. Then they recorded all the calls made by the parents before the chicks were of squawking age and all the calls made by the chicks once they began to call.
What they found was that parents started making signature calls when the chicks were very young, providing a template that the chicks imitated and added their own flourishes to in order to create their names. The templates were learned, not innate: Chicks' names were more similar to the names of the parents that raised them than to their biological parents'.
What's the Context:
Dolphins and humans are, so far, the only other members of this select club of animals who use names for individuals. Scientists think this ability is related to the intensely social lives of all three of these creatures. In the case of parrots, whose flocks often split up and join with other groups, having one's own name and being able to imitate the names of other birds could be a helpful tool when forming new flocks.
The Future Holds: The researchers point out that this mode of learning names is reminiscent of how human infants pick up their names, meaning that parrots could provide a model for how human speech arises. And an interesting corollary, as birds' names are similar to those of their parents and siblings, is that birds' relationships might be inferred from their calls. A chance, perhaps, to suss out the bird equivalent of surnames? Reference: Berg, et al. Vertical transmission of learned signatures in a wild parrot. Published online before print July 13, 2011, doi: 10.1098/rspb.2011.0932
Proc. R. Soc. B (via ScienceNOW
)
